Novelty of Lithium Salt Solution in Sulfone and Dimethyl Carbonate-Based Electrolytes for Lithium-Ion Batteries: A Classical Molecular Dynamics Simulation Study of Optimal Ion Diffusion

The reduction in the usage of fossil fuels can be achieved by focusing on the development of high-energy storage battery. Recently, tetramethylene sulfone (TMS)-based electrolytes have become the center of attraction for Li-ion battery because of their high electrochemical and thermal stability. Our work uncovers the novel effect of adding dimethyl carbonate (DMC) to the mixture of TMS with LiPF6 solvent having different molar ratios of individual constituents by the classical molecular dynamics simulations. We calculated composite electrolyte properties such as solvation structures, diffusion coefficients, and ionic conductivities and found that the coordination between Li+ and PF6- is least for the DMC/TMS ratio of 1:2 because Li ions are found to be more coordinated with TMS molecules, which provides better structural stability to the system. Moreover, the transport properties of this system illustrate that the diffusion of ions is not so encouraging. However, while taking different concentrations of LiPF6 with the same molecular ratio of DMC/TMS, it was found that Li+ and PF6- have more diffusion coefficient and ionic conductivities with the salt/solvent molar ratio of 1:20. However, because of strong interactions of Li-F, we propose a salt/solvent ratio of 1:12 as an appropriate choice based on optimal ion diffusion for better battery performance.